This invention relates to couplers for connecting two shafts together for the purpose of transferring rotational motion from one shaft to the other. The coupler has particular application in the agricultural irrigation field where irrigation pipeline support towers have centrally located drive motors for propelling wheels located at the ends of the towers. The motor""s gear box is connected to worm drives at the wheels by drive shafts. Drive couplers are used to connect the drive shaft to both the motor gear box and the worm drives. Of course couplers could also be used in other applications where two generally aligned but spaced shafts have to be connected such that rotational motion of one shaft is transferred to the other. Additionally, it is quite often desirable that the coupler be able to tolerate some degree of misalignment between the shafts. Misalignment usually takes the form of the shafts not being parallel to one another.
The invention is particularly concerned with situations where the ends of the shafts remote from the coupler have to be fixed in position prior to installing the coupler. Accordingly, the shafts have no axial movement and perhaps little or no transverse movement available with the result that the coupler has to be installed generally between and/or around the pre-installed shafts.
Prior art couplers of the above type are known as split couplers and have what might be described as a built-up construction wherein a plurality of arms are placed about the end of a shaft and bolted together. The arms extend beyond the end of the shaft where they intersect with the arms of the opposite shaft or some intervening third part in some sort of engagement. Sometimes a rubber connecting block is involved to accommodate misalignment but this leads to problems with the rubber block adding lots of torsional movement called wind-up, with attendant backlash problems. In addition to wind-up, a major problem with the built-up construction is the high number of components and the large number of fasteners required. The high part count adds to cost and installation time.
The present invention concerns a coupler for transmitting rotational motion from one shaft to an adjacent but spaced shaft. A primary object of the invention is a coupler whose installation can be completed after that of the shafts and with a minimal number of parts.
Another object of the invention is a coupler of the type described which can accommodate misalignment of the shafts.
A further object of the invention is a coupler that reduces lost torsional movement or wind-up.
These and other objects which may become apparent in the following specification are realized by a coupler for connecting first and second shafts. The coupler has first and second connector elements attached to the ends of the respective shafts. The connector elements each include a plurality of splines defining grooves therebetween. One set of splines is internal and the other external such that the splines of one connector element fit into the grooves of the other connector element to interlock the connector elements in rotationally-driving relation. A sill is attached to the second connector element and defines a pocket into which an end portion of the second shaft can be placed by means of a non-axial relative movement between the sill and second shaft. A clamp member is engageable with the sill to enclose the end portion of the second shaft and fix the shaft in rotationally-driving relation with the second connector element. The clamp has a lug which fits into a slot formed in an end wall of the second connector element.